Means or mechanism for maintaining a film strip upon a film sprocket



April 6, 1954 MENNECKE 2,674,454

H. MEANS OR MECHANISM FOR MAINTAINING A FILM STRIP UPON A FILM SPROCKET Filed July 7, 1949 i I 3 INVENTOR. F

22 M4; fitter/ray Patented Apr. 6, 1954 MEANS 0R MECHANISM FOR MAINTAINING A FILM STRIP UPON A FILM SPROCKET Harold Mennecke, Chicago, 111., assignor to De Vry Corporation, a corporation of Illinois Application July 7, 1949, Serial No. 103,442

I 1 Claim.

This invention relates to certain new and useful improvements in a means or mechanism for maintaining a film strip upon a film sprocket.

Among the several objects of this invention is the provision of a means or mechanism for maintaining a film strip upon a film sprocket in a manner such that the retainer plate of such means or mechanism may be quickly moved into and out of film retaining position with respect to the sprocket without damage to the film strip.

Another and equally important object of the invention is th provision of a simplified and improved construction of a means or mechanism for maintaining a film upon its sprocket.

Other objects will appear hereinafter.

The invention consists in the novel combination and arrangement of parts to be hereinafter described. and claimed.

The invention will be best understood by reference to the accompanying drawings showing the preferred form of construction, and in which:

Fig. 1 is a perspective view of the invention in film retaining position with respect to a sprocket;

Fig. 2 is a side part-sectional detail view of the same showing the invention disposed in a non-operative position with respect to the sprocket;

Fig. 3 is a front elevational view of the same; and

Fig. 4 is a plan view of the same.

The several objects of my invention are accomplished by the preferred form of construction shown in the accompanying drawings, in which drawings It! indicates a wall of a motion picture projecting apparatus with which my invention is associated. Formed as a part of this wall It! is a boss ll through which is journaled a driven shaft !2. On this shaft I2 is mounted a sprocket it having the usual sprocket teeth Hi which are adapted to engage the perforations of a film strip 15.

My improved and simplified film retaining means or mechanism comprises a bracket l6 secured to the wall H) by suitable bolts l1.

This bracket l6 provides spaced lugs I8. Between these lugs I8 is positioned the shank E9 of an arm 20. The shank I 9 is pivotally connected to the lugs l8 by means of pintles 2|.

The outer end of the arm 20 provides a finger button 22 having a knurled surface 23 to afford proper finger gripping of the arm 2!] to pivot the arm 20 about its pivot pins 2 I. Extending from opposite sides of the arm 20 and preferably though not necessarily formed as an integral part thereof are aprons 24 curving to conform to the configuration of th sprocket wheel is and provided with undercut grooves 25 for the reception of the teeth It and guiding ribs Id of the sprocket Wheel it.

The shank IQ provides a socket 225. Mounted in this socket 26 is a latch pin 21 havin a latch head 28 adapted to engage either of two latch notches 29 formed in the back wall 30 of the bracket I6 whereby to releasably latch the arm 2i! in either of its two positions as shown in Figs. 1 and 2.

The latch head 28 and the latch notches 29 are of corresponding shape so that mere pressure upon the outer end of the arm 2% will automatically disengage the latch pin 27 from the latch notches. The latch pin 2'! is yieldably projected in its outermost position by means of a spring 3| mounted in the socket 2t and bearing against the latch pin 2? as shown.

To complete the invention I provide a guard plate 32. This guard plate 32 is mounted upon a reduced portion 33 of the boss Ii. Such a guard plate 32 provides upwardly extending fingers 34 disposed on opposite sides of the shank It. The arrangement is such that when the film strip is projected between the sprocket l3 and the aprons 24, the fingers 34 will prevent the edges of the film strip from being positioned beneath the shank is, where such edge portion would be ruptured upon pivotal movement of the arm 20 to dispose the aprons 224 into film retaining position. Such aprons 24 together constitute a retaining plate for the film strip.

From the foregoing description it is apparent that I have provided a means or mechanism for retaining a film upon the sprocket l 3 which may be quickly and conveniently moved into and from film retaining position without damage or jury to the film strip. The construction disclosed is of a simplified and improved nature of film retaining heretofore employed.

While I have illustrated and described the preferred form of construction for carrying my invention into efiect, this is capable of variation and modification without departing from the spirit of the invention. I, therefore, do not wish to be limited to the precise details of construction set forth, but desire to avail myself of such variations and modifications as come within the scope of the appended claim.

Having thus described my invention, what I claim as new and desire to protect by Letters Patent is:

The combination comprising a bracket adapted for attachment to a wall of an associated machine, means for connecting said bracket to said wall, said bracket provided with spaced apart laterally extending supporting arms, an arm extending laterally in the same direction as said arms and having an enlarged shank at one end thereof adjacent said bracket and a finger gripping portion at the other end thereof, means for pivotally connecting the shank to said bracket between said arms, a retainer plate carried by said arm for positioning upon a film sprocket of said machine over a film strip disposed upon said sprocket, said bracket having a base portion between said arms and opposite the pivotal connection between the shank and said bracket being provided with spaced vertically aligned notches having tapered top and bottom walls, said shank having a socket formed in one end thereof adjacent said bracket and extending in a longitudinal direction with respect thereto, and a spring-urged tapered end detent in said socket and engageable with one of the corre- 4 sponding tapered notches of said base when said retainer plate is positioned upon said film strip and engageable with the other of the notches when said plate is positioned from engagement with said strip.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 920,531 Bradley May 4, 1909 1,764,939 Dina June 17, 1930 1,966,857 Goldhammer July 17, 1934 2,228,092 Sperry Jan. '7, 1941 2,235,029 Levinson Mar. 18, 1941 2,422,310 Nemeth June 17, 1947 2,455,051 Fairbanks Nov. 30, 1948 FOREIGN PATENTS Number Country Date 847,998 France Oct. 19, 1939 

